I was told my generic thyroid pill isn't comparable to the brand-name version. How is this possible? I thought they were all the same.

The FDA requires drug manufacturers to make sure that the body absorbs generic drugs at a similar rate and strength as their brand-name counterparts. Although generics aren't exact copies, for the most part they are as effective as their pricier version. But the absorption rate of some hormonal drugs, including thyroid pills such as yours, can vary slightly between the generic and branded forms, and the difference may be enough to change how you respond to the medication. That's why in this case, many doctors prefer to prescribe the brand-name medication by writing DAW (dispense as written) on your Rx.